This invention relates generally to storage tanks and more particularly concerns the mounting of bladders used to line tanks storing fertilizer and other corrosive materials.
Tanks used for storing fertilizer, oil, petro chemicals and the like are presently lined by suspending a bladder of unreinforced PVC or other material suited to the specific application from J-hooks mounted along the upper interior periphery of the tank. In such arrangements, the bladder is spaced inwardly from the tank sidewalls by as much as 2 inches and to the base portion of the bladder which rests on a bed of sand at the bottom of the tank. One ton of sand for every foot of diameter of the tank is distributed over the bottom of the tank and under the bladder. Since the bladder is spaced inwardly from the tank, condensation builds up between the tank wall and the bladder and causes the tank to corrode. In addition, overfill above the level of the J-hooks supporting the bladder in the tank causes the highly corrosive stored material to flow over the bladder and between the tank and bladder to the sand below. The sand must then be replaced. In a fifty foot diameter tank, this involves the removal and replacement of some fifty tons of sand. Many tanks are up to 200 feet in diameter. The down time and costs of tank repair and sand replacement can clearly be quite burdensome.
It is, therefore, an object of this invention to provide a storage tank bladder seal which minimizes the occurrence of condensation between the tank wall and the bladder. A further object of this invention is to provide a storage tank bladder seal which eliminates spacing between the upper peripheral portions of the tank and the bladder. Another object of this invention is to provide a storage tank bladder seal which minimizes the possibility of overfill materials penetrating between the tank and the bladder. Similarly, it is an object of this invention to provide a storage tank bladder seal which will minimize the possibility of the tank contents contaminating the sand base at the bottom of the tank. Collaterally, it is an object of this invention to eliminate the use of sand as a base material in the tank.